3.12 Pharyngitis (Sore Throat)

Presentation

The patient with a bacterial pharyngitis complains of a rapid
onset of throat pain worsened by swallowing. There is usually a fever,
pharyngeal erythema, and a purulent, patchy, yellow, gray or white
exudate, tender cervical adenopathy, headache and absence of cough.
Viral infections are typically accompanied by conjunctivitis, nasal
congestion, hoarseness, cough, aphthous ulcers on the soft palate and
myalgias. It is helpful to differentiate pain on swallowing
(odynophagia) from difficulty swallowing (dysphagia), the latter being
more likely caused by obstruction or abnormal muscular movement.

What to do:

First examine the ears, nose, and mouth, which are, after all,
connected to the pharynx, and often contain clues to the diagnosis.

Depress the tongue with a blade, have the patient raise his soft palate
by saying " ah," inspect the posterior pharynx, and swab both tonsillar
pillars for a culture. (You can decide later whether you really need to
plant the culture. Rapid strep tests may provide results in a few
minutes, while cultures may take 1-2 days to incubate and interpret.
This delay does not alter the effectiveness of therapy, however.
Treatment may begin up to nine days after symptoms and still prevent
rheumatic fever.)

If you are in the middle of an epidemic of group A streptococcal
pharyngitis; if the patient is between 3 and 25 years old, has a history
of rheumatic fever and recurrent "strep throats" and has been exposed;
and if the patient has a red throat, fever, tender anterior cervical nodes,
and no viral URI symptoms (or any convincing subset of the above);
give antibiotics. Throat culture is optional, at the preference of the
follow-up physician. The recommended treatment for streptococcal
pharyngitis is oral penicillin VK 250mg q8h for 10 days. Injectable
penicillins are preferred for patients unlikely to finish ten days of pills
and those with a personal or family history of rheumatic fever. Patients
under 60 lbs (30 kg) get one intramuscular injection of benzathine
penicillin G 600,000 units and those over 60 lbs get 1,200,000u im. For
those allergic to penicillin give erythromycin 250mg qid (or 333mg of
erythromycin base tid) for 10 days. Amoxicillin offers no significant
advantage for treating group A strep.

When the infection is not clearly bacterial or you are unsure about the
need for an antibiotic (or you or the patient "need to know" if this is a
strep infection) then you may obtain a rapid strep test. If the rapid strep
test is positive, then treat with antibiotics as above. If the test is
negative or unavailable and you have a high clinical suspicion that this
is a viral pharyngitis, provide symptomatic treatment (below), send a
culture, and hold antibiotics pending results.

If you suspect mononucleosis, draw blood for atypical lymphocytes
and a heterophile or monospot to confirm the diagnosis (see below).

Relieve pain with acetaminophen ibuprofen, aspirin, warm saline
gargles, and gargles or lozenges containing phenol as a mucosal
anesthetic (e.g., Chloraseptic, Cepastat). A one-to-one mixture of
diphenhydramine and kaolin-pectin suspension can also provide
temporary relief of throat pain. Viscous Xylocaine gargles anesthetize
the throat but patients may still have difficult swallowing because of the
lack of sensation. For severe pain in patients without contraindications,
dexamethasone 10mg im once has been used along with antibiotics.

What not to do:

Do not miss an acute epiglottitis or supraglottitis. In a child, this
presents as a sudden, severe pharyngitis, with a gutteral, rather than
hoarse voice (because it hurts to speak), drooling (because it hurts to
swallow), and respiratory distress (because swelling narrows the
airway). Adults usually have a more gradual onset, over several days,
and are not as prone to a sudden airway occlusion, unless they present
later in the progression of the swelling, already with some respiratory
distress.

Do not give ampicillin to a patient with mononucleosis. The resulting
rash helps make the diagnosis, and does not imply ampicillin allergy,
but can be uncomfortable.

Do not miss abscesses, which usually require hospitalization and
intravenous penicillin, if not drainage. Peritonsillar abcesses or cellulitis
make the tonsillar pillar bulge towards the midline. Retropharyngeal
abscesses (and epiglottitis) may require soft tissue lateral neck films to
visualize.

Do not miss gonococcal pharyngitis, which can produce a mild
clinical syndrome and requires special cultures on Thayer-Martin
medium.

Do not miss the rare but deadly causes of sore throat. A patient with
paresthesia at the site of an old, healed bite and painful spasms when he
even thinks of swallowing may have rabies. A patient with facial palsy,
myocarditis, and a tough, white, membrane adherent to the posterior
pharynx may have diptheria. You cannot diagnose them unless you
think of them.

Discussion

The general public knows to see a doctor for a sore throat, but
the actual benefit of this visit is unclear. Rheumatic fever is a sequela
of about 1% of group A streptococcal infections, and only about 10% of
sore throats seen by physicians represent group A streptococcal
infections. Post-streptococcal glomerulonephritis is usually a self-
limiting illness and is not prevented with antibiotic treatment. Penicillin
therapy does avoid acute rheumatic fever and may sometimes reduce
symptoms or shorten the course of a sore throat. Antibiotics probably
inhibit progress of the infection into tonsillitis, peritonsillar and
retropharyngeal abscesses, adenitis, and pneumonia.

Group A streptococcal infection cannot be diagnosed reliably by
clinical signs and symptoms. Typically, a quarter of throat cultures
grown group A strep, and half of those represent carriers who do do not
raise anti-streptococcal antibodies and risk rheumatic fever. Rapid strep
screens are less sensitive than cultures. The best approach to the
identification and treatment of streptococcal pharyngitis depends on the
prevalence of group A streptococcal infection in the patient population,
the cost and availability of culture and rapid test methods, the reliability
of communication and follow up and the relative values of cost,
antibiotic overuse, and adverse outcomes.